Perl programming - useful for automating many tasks related to system administration
or text processing.

Python programming - same as above, and also useful for cross-platform end-user GUI applications

Bash shell scripts - use bash for any number of useful things on a Linux system

Linux system administration and consulting - need help figuring out how to do something
on a Linux box, or figuring out how to put Linux to work for you? I can help.
I am a Linux tech support specialist.
Linux can be put just about anywhere these
days, and you may be able to save a boatload of money with it, depending on your application.

C and C++ programming - for high performance specialized applications

Apache web server - installation and configuration

Java programming - cross-platform GUI applications

While you're grabbing the Yahtzee program for your computer, perhaps consider searching 123 CCTV for other computer programs. There's one in particular that will allow you to view CCTV Cameras from anywhere in the world, just as long as they're tied into your computer which is hooked up to the internet!